Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to disk drive suspensions, and more particularly to disk drive suspension load beams that are more easily manufactured to exacting specifications, such as more precise spring rates (vertical stiffness of the load beam) and 1st torsion values. In a particular aspect, a difficult to control variant in the manufacturing process, the spring portion-etching step to reduce the spring portion thickness relative to the rest of the load beam, is eliminated. The invention provides an interrupted load beam in which the original spring portion of the load beam is removed and the metal layer of a flexible conductor laminate substituted for that original spring portion of the load beam. This metal layer is precise in thickness and thus highly predictable in performance. The invention provides the suspension apparatus, the method of making the suspension apparatus, and the method of applying force to a slider by means of the novel spring arrangement of the apparatus.
2. Description of the Related Art
Suspension load beams are well known and typically have a base portion that attaches to a mount plate connected to an actuator arm, a spring portion and a rigid portion that mounts a flexure and slider for positioning the slider precisely at a selected track on a disk. Rigidity or stiffness in the forwardmost beam portion of the load beam is desirable for many performance-related reasons. The spring portion on the other hand is desirably less stiff, especially in relatively short load beams such as 11 mm and 14.5 mm lengths, in order to provide the desired spring rate and 1st torsion values for the suspension. Etching away a part, e.g. 50-70% of the load beam spring portion thickness is the expedient commonly employed to reduce thickness Partial etching of the very thin load beam is problematical because precise control of the etching process is not readily achieved. Etching tolerances of as much as 20% are required. Because spring rate change is the cube of a change in thickness, the noted etched thickness tolerance can produce as much as a 70% change in spring rate, and a 20-40% change in the 1st torsion value.
It is an object, therefore, of the invention to provide an improved disk drive suspension having an interrupted load beam. It is a further object to provide a load beam of improved design. A further object is to provide a load beam in which the spring portion thickness is precisely controlled and achieved without etching. Yet another object is to use the steel layer or metal foil forming a part of the flexible conductor laminate of the wireless suspension to provide a spring portion to the load beam, the original load beam spring portion having been removed as part of the load beam forming process. A further object is to provide a method of manufacturing load beams in which the thickness of the rigid or beam portion is unrelated to the thickness in the spring portion. A still further object is to provide a load beam having precisely controlled thickness in the spring portion, and greater thickness in the rigid or beam portion.
These and other objects of the invention to become apparent hereinafter are realized in an interrupted load beam having a base portion and a rigid portion spaced from each other across an interruption along the length of the load beam, a flexible conductor flexure attached to the load beam, the flexible conductor flexure comprising conductive traces, an insulating dielectric and a spring metal layer, the flexible conductor spring metal layer being attached to the load beam base portion and to the load beam rigid portion to join the rigid portion to the base portion in springing relation.
In this and like embodiments, typically, the load beam base portion has a projecting section extending in parallel with the load beam, and includes also an elongated mount plate arranged to overlie the base beam projecting section, the flexible conductor has a distal end, the flexible conductor distal end comprising an open frame formed from the flexible conductor spring metal layer and a flexure tongue supported by the frame for carrying a slider, the flexible conductor comprises a laminate of the spring metal layer, the insulating dielectric and the conductive traces, the insulating dielectric and the conductive traces traversing the load beam interruption in flexible conductor spring metal layer supported relation, and the insulating dielectric and conductive traces are bifurcated forwardly of the load beam interruption and along the length of the load beam rigid portion, and rejoined at the flexure frame.
In a further embodiment, the invention provides a disk drive suspension comprising a flexure and an axially elongated load beam of a predetermined thickness, the flexure being adapted to carry a slider and comprising a flexible laminate of a spring metal layer of less thickness than the load beam predetermined thickness, a dielectric layer, and one or more pairs of insulated conductive traces disposed on the dielectric layer, the load beam having a base portion for mounting the load beam to an actuator and a rigid portion, the rigid portion being spaced from the base portion to define an interruption along the axial length of the load beam, the flexure being attached to the load beam rigid portion, the flexure spring metal layer having a continued extent extending over and beyond the load beam rigid portion and over the load beam base portion, the spring metal layer continued extent being fixed to the load beam base portion and to the load beam rigid portion on opposite sides of the load beam interruption to springingly couple the load beam portions together.
In this and like embodiments, typically, the flexible laminate flexure has a distal end comprising an open frame formed from the flexible laminate spring metal layer and a flexure tongue supported by the frame for carrying a slider, the flexible laminate insulating dielectric and conductive traces traverse the load beam interruption in flexible laminate spring metal layer supported relation, the insulating dielectric and conductive traces are bifurcated forwardly of the load beam interruption and along the length of the load beam rigid portion, and rejoined at the flexure frame, and the load beam rigid portion is free of edge rails.
In its method aspects the invention provides a method of manufacturing a disk drive suspension comprising a load beam and a flexible conductor that defines a flexure, including etching from a web a load beam having a base portion, a spring portion and a rigid portion, etching away a part of the spring portion, attaching to the load beam the flexible conductor in flexure-defining relation, the flexible conductor comprising a laminate of a spring metal layer, a dielectric layer and insulated conductive traces, the flexible conductor having its the spring metal layer attached to the load beam base portion adjacent the spring portion and to the load beam rigid portion adjacent the spring portion with its the dielectric layer and conductive traces traversing the spring portion, and etching away the balance of the spring portion so that the sole spring connection between the base portion and the rigid portion is the flexible conductor spring metal layer that also forms the flexure.
In this embodiment, typically, there is further included shaping the load beam spring portion to have lateral extensions extending beyond the lateral edges of the base portion and the rigid portion, etching away all of the spring portion except the lateral extensions, and etching away the lateral extensions after attaching the flexible conductor to the load beam base and rigid portions; welding at laterally and longitudinally distributed locations adjacent the locus of the load beam spring portion the flexible conductor spring metal layer to the load beam base portion and to the load beam rigid portion, and maintaining the flexible conductor spring metal layer generally free of dielectric layer and conductive traces in the locations of welding of the spring metal layer to the load beam base and rigid portions.
In a further embodiment, the invention provides a method of applying a load on a slider carried by a disk drive suspension comprising a load beam having a base portion and a rigid portion spaced across an interruption where the load beam spring portion was located, including spring coupling the load beam base and rigid portions with a spring metal layer from a flexible conductor comprising the spring metal layer, a dielectric layer and conductive traces in lieu of the original spring portion of the load beam, and applying a force to the slider from the flexible conductor spring metal layer, and forming a flexure for supporting the slider from the flexible conductor.